Automatic safety test device for hydraulic elevators

Abstract: The test assembly acts on a slack rope device (4,5,6) for activating a safety system (8) of the elevator. The test assembly includes an attachment strap (2, 15) of a rope (1) slideably engaged with a fastening device (1), a flange (14) carried on said attachment strap (2,15), above said fastening device (1), a system of levers (9,10, 12) engaged with said flange (14) to prevent movement of the attachment strap (2, 15) and means (16) for remote activation of the lever system (9, 10, 12). Activation of the system of levers (9,10,12) permits movement of the rope (3) sufficient to activate the slack rope device (4,5,6).

Description: The present invention concerns an assembly to facilitate testing of safety mechanisms in hydraulic elevators. As is well known, hydraulic elevators can be actuated directly or indirectly. In the latter type of elevators, a piston or.pistons are connected to the framework of the car by means of a series of ropes, which are, in turn, sent back over pulleys. As is obvious, in this type of elevator it is also necessary to provide safety mechanisms that intervene in case a rope slackens, i.e., loses tension, or breaks. Generally, a speed governor is used to prevent the rate of descent from exceeding a predetermined value. In some configurations a slack rope system is provided instead of a governor. Such a mechanism, used along with a rupture valve over the piston, substitutes for the governor. In case a rope breaks or loses tension, small wheels provided along the running guides of the elevator car are automatically pressed against the running guides, thus stopping the travel of the elevator car. When a new elevator is installed, a building inspector is expected to test the efficacy of the safety mechanisms, such as the slack rope system. According to the standard procedures, such a test must typically be effected outside of the hoistway. Therefore, a device that allows a slack rope condition to be simulated must be provided to be able to conduct such a test before the system is approved. Currently the cars of hydraulic elevators are mounted on a framework consisting of two uprights and a base. On each upright are the slide runners or rollers of the elevator car and a safety plate. The safety plate includes a roller that moves vertically and which, if activated, presses against the guide, stopping the elevator car. Each of the rollers is engaged by a torsion bar that actuates the rollers. If a slack rope device is installed on the elevator, the building operators may adopt several solutions to allow the test to be conducted by the inspectors. One solution includes the steps of directly connecting a rope to the torsion bar and pulling it from the pit to engage the rollers with the guide and thereby block the full path of travel of the elevator car. As can be understood, this system is not particularly efficacious in that it does not actually de-tension the rope. In other devices, straps are mounted onto the guides and directly onto the framework of the elevator car. The straps on the car are used to keep the torsion bar of the safety system in the rest position by means of the pressure of the springs of the hoist ropes. As the elevator car moves downward in the hoistway, the straps fixed onto the guides engage those arranged on the framework of the elevator car, releasing the springs that actuate the torsion bar of the safety system, thereby stopping the elevator car. This type of device requires the operator to go into the hoistway of the elevator car after the test to remove the strap from the framework of the elevator car. This activity is not always acceptable according to the standards in effect. Most of the solutions proposed to date are structurally complicated and, furthermore, may take up to two to three hours for each individual test to be conducted. DE-A-3232213 discloses a test assembly for facilitating safety tests in an elevator having a slack rope device, the test assembly including: a fastening device for a rope; means for attaching a rope to said fastening device; abutment means carried on the attachment means; means for engaging the abutment means to prevent relative movement between the abutment means and the fastening device; and means for remotely disengaging the engagement means from the abutment means, wherein such disengagement permits movement of the attachment means relative to the fastening device sufficient to activate the slack rope device. The present invention is characterised over DE-A-3232213 in that the means to engage the abutment includes a support on which a first and a second lever are hinged, and wherein in the deactivated position of the device, one end of the first lever is engaged with the abutment means and its opposite end is positioned above one end of the second lever, the means of remote disengagement being connected to the opposite end of the second lever, the two levers being positioned with respect to each other in such a way that, when the means to remotely disengage is acted upon, the second lever rotates, releasing the end of the first lever with which it is engaged, allowing the first lever to rotate and thereby release the abutment means. Thus, according to the present invention, a test assembly operates to permit movement of a rope by an amount sufficient to activate the elevator's slack rope system. The test assembly preferably includes an attachment strap of one of the ropes which, upon activation of the test assembly, is permitted to slide in relation to a fastening device of the rope. The movement of the rope is an amount at least sufficient to activate the slack rope device. The test assembly further preferably includes a flange carried on the attachment strap above said fastening device. According to a particular embodiment of the invention, the means to engage includes means to prevent unauthorized activation of the test assembly. The means includes a safety pin positioned to prevent pivoting of one of the system of levers. According to a further particular embodiment, a return spring is provided over the attachment strap, below the fastening device of the ropes. After activation of the test assembly, the return spring is compressed between the fastening device and the end of the attachment strap. The compressed spring urges the rope to return into its initial position such that the system of levers may be repositioned to engage the flange and block any further movement of the rope. A preferred embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic view of one embodiment form of a test assembly according to the invention, with the test assembly deactivated; Figure 2 is a schematic view of a slack rope device for activation of a safety device in an indirect hydraulic elevator, connected to the test assembly of Figure 1; Figure 3 is a schematic view of an embodiment form of a test assembly according to the invention, with the test assembly activated; and Figure 4 is a schematic view of a slack rope device for activating a safety device in an indirect hydraulic elevator, connected to the test assembly of Figure 3. Referring to all four figures of the attached diagrams, and particularly first to Figure 1, one embodiment of the test assembly according to the invention is illustrated. A fastening device 1 is located in the pit of the hoistway. Straps 2 of two ropes 3 are attached to the fastening device. The opposite end of each rope 3 (see Figure 2) is connected to block 4, with a spring positioned around it and compressed between block 4 and plate 6. Blocks 4 are proximate to lever 7. Engagement between blocks 4 and lever 7 causes the activation of the safety device. The safety device is illustrated generically with reference number 8, as it does not form part of the invention. Referring back to Figure 1, fixed block 9 is mounted on the fastening device 1. A first lever 10, hinged at point 11, and a second lever 12, hinged at point 13, are hinged on the fixed block 9. The first lever 10 is shown in a substantially horizontal position, in the deactivated condition shown in Figure 1, with one of its ends--the front one--engaged with flange 14 positioned over the threaded part 15 of strap 2, above fastening device 1, and with the other end engaged with the upper end of lever 12. The lower end of lever 12, which is found in a substantially vertical position in the deactivated condition of Figure 1, is connected to line 16. Line 16 provides means to activate the test assembly. As can be seen in Figure 1, threaded part 15 extends below fastening device 1 by a much larger amount than the corresponding threaded part 15 of the other strap 2, over which the test assembly is not provided. The threaded part 15 carries spring 17, which is positioned between fastening device 1 and nut and lock nut system 18, screwed to the end of threaded part 15. The extent of threaded part 15 below fastening device 1 is determined so as to allow, as will be more evident later, rope 3 to move at least enough to activate safety device 8. Finally, a safety pin 19 is provided on block 9. The safety pin provides means to prevent activation of the test assembly by an unauthorized person or accidental activation. The starting situation is that shown in Figures 1 and 2. After safety pin 19 is removed--the only operation that must be carried out in the pit, and in any case not while the test is being run--the test assembly is in condition to be activated. Note that the presence of the pin is purely for safety, and after it is removed the elevator is still sound and functioning. Thus, when the test is to be done it will suffice to pull line 16, from any position, for example from the courtyard, from the street, from the building entrance, etc. Pulling line 16 results in lever 12 rotating around pin 13, and thus its end disengages from lever 10. Lever 10 will then rotate around pin 11 and remove the impediment that it imparted to flange 14. By the action of spring 5, which is initially compressed (see Figure 2), rope 3 will move upward an amount corresponding to the already mentioned amount of threaded part 15 below fastening device 1, compressing spring 17 at the same time. As mentioned above, the length of the segment of threaded part 15 below fastening device 1 is such as to allow rope 3 to move enough to activate device 8. As a result, the elevator will be stopped by safety device 8. The test assembly and safety device 8 are now in the situation illustrated in Figures 3 and 4. The test assembly is realized further in such a way as to be restored automatically. A typical hydraulic elevator has an automatic valve that, when activated, makes the pulleys drop even a little lower. At this point spring 17 can lengthen, bringing flange 14 back to a position in which it can be reengaged by the end of lever 10. In any case, it should be noted that the restoration would occur even in the absence of spring 17, simply by the force of gravity. From the above it will be seen that in its preferred embodiments at least the invention provides a simple, easy to use test assembly for safety testing hydraulic elevators, which does not require long preparation times and that can be used quickly, and which allows the entire test to be conducted without the need to go into the hoistway. The present invention has been described by way of non-limiting illustration, according to its preferred forms of realization, but it is to be understood that variations and/or modifications may be added by those skilled in the art without thereby exceeding the relative scope of protection, as defined by the appended claims.

Claims: A test assembly for facilitating safety tests in an elevator having a slack rope device, the test assembly including: a fastening device (1) for a rope (3); means (2,15) for attaching a rope to said fastening device (1); abutment means (14) carried on the attachment means (2,15); means (10) for engaging the abutment means (14) to prevent relative movement between the abutment means (14) and the fastening device (1); and means (16) for remotely disengaging the engagement means (10) from the abutment means (14), wherein such disengagement permits movement of the attachment means (2) relative to the fastening device (1) sufficient to activate the slack rope device; characterised in that the means to engage the abutment includes a support (9) on which a first (10) and a second (12) lever are hinged, and wherein in the deactivated position of the device, one end of the first lever (10) is engaged with the abutment means (14) and its opposite end is positioned above one end of the second lever (12), the means of remote disengagement (16) being connected to the opposite end of the second lever (12), the two levers (10,12) being positioned with respect to each other in such a way that, when the means to remotely disengage is acted upon, the second lever (12) rotates, releasing the end of the first lever (10) with which it is engaged, allowing the first lever (10) to rotate and thereby release the abutment means (14). The test assembly according to claim 1, further including means (19) to prevent activation of the test assembly. The test assembly according to claim 2, wherein the means to prevent activation of the test assembly includes a safety pin (19) engaged with the engagement means (10). The test assembly of any of the preceding claims wherein said abutment means comprises a flange (14). The test assembly of any of the preceding claims wherein said abutment means (14) is arranged above said fastening device (1). The test assembly of any of the preceding claims wherein said attachment means comprises a strap (2). The test assembly according to any of the preceding claims, further including a return spring (17) disposed between the fastening device and the end of the attachment means. The test assembly according to any of the preceding claims, wherein the means to remotely disengage includes a cord (16) connected to the means (10) to engage the abutment means (14).

Inventors: ADIFON LEANDRE, GUAITA ERMINIO, VAILATI CARLO, ADIFON, LEANDRE, GUAITA, ERMINIO, VAILATI, CARLO
Applicants: OTIS ELEVATOR CO, OTIS ELEVATOR COMPANY
Application year: 1994
Main classification: B66B5
IPC codes: B66B5, B66B9, B66B7